Apparatus for pasteurizing liquids



y 19400 R. SELIGMAN 2,201,056

APPARATUS FOR PASTEURIZING LIQUIDS Filed Oct. 15, 1939 R ICHARD S ELJGMAN After/rays Patented May 14, 1940 PATENT OFFICE 2,201,050 4 APPARATUS FOR PASTEURIZING L'IQUIDs Richard Seligman, Point Pleasant, Wandsworth, London, England, assignor to The Aluminum Plant & Vessel Company Limited, Point Pleasant, Wandsworth, London,

British company England, a

Application October 13, 1939, ,Serial No. 299,372

In Great Britain November 9, 1938 2 Claims.

This invention relates to means for operating heat exchange apparatus and has particular ref erence to the pasteurization of liquids which may be heated by direct admission of steam.

The invention is more particularly concerned with a means for pasteurizing such liquids by the employment of a plate-type heat exchanger. but it is to be understood that other forms of heat exchanger may, if desired, be employed.

According to the invention there is provided a means for efiecting the pasteurization of liquids which may be heated by direct admission of steam wherein steam is introduced into the liquid through aninjector by which the liquid is drawn through a heat exchanger wherein the liquid is pro-heated by the mixture of liquid and condensed steam discharged from the injector and forced through the heat exchanger.

In order that the said invention may be clearly understood and readily carried into effect, the same will now be more fully described with ref erence to the accompanying drawing in which- Fig. l is. a view illustrating diagrammatically one mode of carrying out the invention; and

Fig. 2 is an end view of the arrangement shown in Fig. 1.

In the arrangement illustrated the tank a containing the liquid to be pasteurized is con nected with the inlet 1 of a heat exchanger 9, for example, a plate-type heat exchanger, so that the liquid passing from the tank is caused to pass through the heat exchanger, or a section of the heat exchanger, for the purpose of being subjected to a preliminary heating by heat exchange with some of the liquid, already or previously heated. For the purpose of illustration, the liquid to be pasteurized may, during thisstage of its treatment, be assumed to traverse the path indicated by the chain-dotted line'A. After being thus preliminarily heated, the liquid is caused to pass through a pipe h with which is connected a steam injector d where the steam necessary to raise its temperature to the pasteurizing temperature is mixed with it. The heated liquid is then passed to the inlet m of the heat exchanger and. caused to pass through the heat exchanger, or a section thereof, so that it becomes cooled by heat exchange with incoming liquid passing to the steam injector d. At this stage the liquid may be assumed to traverse the path indicated by the line B. The steam injector is utilized not only for the purpose of supplying the steam required for raising the temperature of the liquid to the pasteurizing temperature but also for the purpose of promoting and maintaining the circulation of the liquid to be pasteurized. In cases in which it is desired that the liquid being pasteurized shall be held at an at elevated tempera ture for a predetermined period before being cooled, a holding chamber or zone may be provided at a convenient position in the heat exchanger or between the steam injector and the point at Which the liquid is returned to the heat exchanger or the portion thereof to be utilized for the cooling of the heated liquid. If the steam injector is, as, indicated in the arrangement illustrated, arranged externally of the heat exchanger, such a holding chamber may, if desired, be provided by fitting a U-shaped pipe n in position between the point at which it is returned to the heat exchanger for cooling or by forming an enlargement of the flow passage in this region. It will be appreciated that the quantity, condition and temperature of the steam must be regulated and governed according to the nature and characteristics of, the liquid to be pasteurized and the pasteurizing temperature to which it is to be raised and that precautions must be taken to prevent over-heating of the liquid. Preferably, a thermometer c is provided at a convenient point.

Having now particularly described and ascertained the nature of my said invention and in the manner the same is to be performed, I declare that what I claim is:

1. Means for pasteurizing liquids by the direct admission of steam, comprising a heat exchanger provided with an inlet for the liquid to be pasteurized, passages in the heat exchanger for the liquidto be heated, other passages in the heat exchanger for the flow of heated liquid in heat exchange relationship with the liquid to be heated, a liquid outlet, a steam injector external to the heat exchanger and connected with the liquid outlet of the heat exchanger, said steam injector serving to inject steam directly into the liquid and also to draw the liquid through the first-mentioned passages in the heat exchanger, and means connecting the discharge of the steam injector with said other passages in the heat exchanger whereby the mixture of heated liquid and condensed steam discharged from the injector is forced by the latter back through the heat exchanger in heat exchange relationship with the liquid passing to the injector for heating.

2. Means for pasteurizing liquids by the direct admission of steam, comprising a heat exchanger provided with an inlet for the liquid to be pasteurized, passages in the heat exchanger for the liquid to be heated, other passages in the heat exchanger for the flow of heated liquid in heat exchange relationship with the liquid to be heated, a liquid outlet, a steam injector external to the heat exchanger and connected with the liquid outlet of the heat exchanger, said steam injector serving not onlyto inject steam directly into theliquid'b'ut also to draw the liquid to be heated through the first-mentioned passages in the heat exchanger, means connecting the dis-t: 1U charge of the steam injector with said other I exchanger.

. RICHARD SELIGMAN. 

